Spark-plug



F. ROBINSON.

SPARK PLUG.

APPLICATION FILED JULY 15.1918.

1,347,662. u y27, 19 0. I {51 I UNITED STATES PATENT omen.

' FRANK ROBINSON, OF CHICAGO, ILLINOIS.

SPARK-PLUG.

Specification of Letters Patent,

Patented July 2'7, 1920.

,Application filed July 15, 1918. Serial No. 245,045.

als of reference marked thereon, which form a part of this specification.

In the construction of spark plugsconsiderable trouble is usually experienced in properly adjusting the spark plug terminals a proper distance apart to produce sparking. The difficulty has been found to exist in the construction of the terminal parts, which when assembled often fail to afford a proper spark gap, resulting in. the faulty operation of the spark plug.

This invention relates to an improved form of an internal combustion engine spark plug wherein the spark plug terminal members are so constructed that when assembled within the spark plug they are properly positioned with respect to one another to produce a desired spark gap, without necessitating any adjustment of parts.

It is an object of this invention to construct a spark plug provided with terminal members which when assembled, due to their construction, are always properly spaced from one another to provide a de sired spark gap. v

Another object of the invention is the construction of a spark plug having theterminal members spaced in overlapping position with respect to each other to insure a proper spark gap therebetween.

It .is a further'object of the invention to provide a spark plug having the spark plug terminal members axially alined with one another to afford a proper spacing of the terminal pins between adjacent sides thereof.

.It is furthermore an object of the invention to provide a spark plug having the spark terminals spacedrside by side.

It is an important object of this invention to. construct a spark plug wherein spaced overlapping terminals form part of axially alined spark plug terminal members for insuring the proper spacing of the terminals when the plug is assembled.

Other and further important objects of this invention will be apparent from thedisclosures in the specification and drawlIl The invention (in a preferred form) is illustrated in the drawings and hereinafter more fully described.

On the drawings:

Figure 1 is a side elevation of a spark plug embodying the principles of this in vention.

Fig, 2, is a section taken on line 2--2, of

F1? 1, with parts shown in elevation.

1g. 3 is a sectional view taken on line 3-3, of Fig. 2;

4 is a section taken on line 4-4, of

ig. 5 is a section taken on .line 5-5, of,

fiig. 6 is an enlarged fragmentary detail section taken through the lower end of the spark 'plug and showing the method of 'mounting the lower terminal member in position.

Fig. lower terminal member, with parts in elevation. v

As shown on the drawings:

The reference numeral 1, indicates a metal spark plug sleeve, base member or shell, having an externally threaded open plug 2,

integrally formed on thelower end thereof,

and an internally threaded integral hexagonal nut portion 3, formed on the upper end thereof to permit a wrench to be engaged therewith for mounting the base on an engine cylinder. Formed within the base 1, is an upper annular shoulder 4, and a lower annular shoulder5. The lower end of the plug 2, is beveledor tapered as denoted by the reference numeral 6, and is axially drilled to afford a recess 7 and a sharp annular edge or rim 8.

A lower electrode or terminal member is rigidly secured axially in the plug 2, and

comprises a metal stem, spindle or post/ 9,,

the upper end of which is reduced in diameter to afford a shoulder upon which is securelv'seated a downwardly curved hood or baflie plate 10.' Rigidly secured axially in the upper'end of the post 9, and projecting thereabove is a spark terminal pin or 7 is a central vertical section of the 3' roe electrode tip 11. Riveted orotherwise rigidly secured axially to the lower end of the post' 9, is a flat steel ring, spider or stamping 13, provided with gas ports or openings 116 14, between the radial spokes 15, thereof. The lower electrode 915, is projected axially into the lower open end of the base plug 2, to permit the gas ported spider 13, to seat in the plug recess 7. To rigidly hold the lower electrode co-axially disposed in position within the plug 2, the metal rim 8, is forced inwardly beneath the spider'l3,

to form a retaining bead 16. v

Removably disposed within the base 1, is an axially passaged insulating member or core made of porcelain or other suitable insulating material. Said core comprises a neck 17, an enlarged collar or intermediate portion 18, and a chambered tailportibn 19, all integral. Disposed upon the shoulder 4, is a packing ring or washer 20, and seated thereon is the lower end of the core collar '18. The chambered tail portion 19, of the porcelain core rojects into the plug portion 2, of the also to within a short distance of the shoulder 5, and communicates with a chamber in the lower portion of the plug 2, to form a combustion chamber 21.

Projecting axially'through the longitudinally passaged insulating core is a priming tube 22, externally.threaded at both projecting ends thereof. Disposed around the ower projecting end of the priming tube is a washer 23, which is held in position against the porcelain core by means of a lower electrode or terminal member embracing an internally'threaded ring or nut 24, having'integrally formed at one side of the lower end thereof a terminal pin or electrode tip 25, which pro'ects downwardly parallel and toone side 0 the lower termi the lock ring 27, is a primin nal in 11, and properl spaced therefrom to a 0rd a spark gap. lane to the co-axial arrangement of the lower electrode member and the upper electrode member, the terminal tips 11 and 25,- when the spark plug is assembled, are always properly spaced side by side with the proper spark gap therebetween. The electrode ring 24, and the washer 23, are locked in sealing relation with the core, by means of a packing 26,

and a knurled lock ring 27, which is threaded upon the upper rojecting end of the primlng tube 22. helook ring-27, seats tightly against the up r end of the porcelain core neck 17, hol ing said packing 26, seated aroundthe tube in a recess-formed for the purpose in the uppere'nd of the core neck 17 I Removably threaded upon the upper proecting end of the priming tube 22, above 28, which communicates with t e passage in said priming tube. To removably hold. the rcelain core in position seated within the ase 1, a threaded gland or lock nut 29, is threaded into the upper internally threaded nut portion 3, of said base, and presses against a washer mechanism 30, resting on the enlarged portion 18, of the core to clamp the core in place sealed and axially alined within the base.

The co-axial arrangement of the parts of the spark plug, permits the same to be quickly assembled and insures a proper spacing of the electrode tips 11 and 25, without requiring any adjustment. It will also be noted that all of the spark plug partsjmay be readily removed for cleaning or repairs.

I am aware that numerous details of construction may be varied through a wide range without departing from the principles o f this invention, and I therefore do not purpose limiting the patent granted otherwise than necessitated by the prior art.

I ,claim as my invention:

, 1. A spark plug embracing a base, an electrode axlally disposed therein, an insulating member axially seated within said base and having a chamber therein into which said electrode projects, priming means axially secured Within said insulating member, and a second electrode secured on said riming means within said chamber and over apping said first electrode to form a spark gap between the adjacent sides of said electrodes. 2. A spark plu comprising a base, an electrode axially disposed therein, an insulating member seated axiall in said base and inclosing the upper on of said electrode, means for holding said insulating member secured in position, priming means projecting axially through said insulating member, a ring secured on the lower projecting end of said riming means withln said msulatin formed on sai ring to one side thereof and spaced to one side of said first mentioned electrode within said insulating core. 3. A spark plug comprising a shell, a chambered plu mem r, and an electrode formed on the lower end thereof, a cham red insulating core within i said shell registering with said chambered plug to form a combustion chamber, and spark terminals secured to said plug and to v said core, said spark terminals overlapping one another within said insulating core an spaced apart to form a spark gap between the adjacent sides thereof.

4. In a spark plug, a base having a recess in the lower end thereof, an apertured stain ing rigidly seated therein, a rod. secure thereon and projecting axially into 'said'base, bafile cleaning means mounted on said rod, an electrode mounted in the upper end of said rod-and co-axial therewith, an insulating core seated withinsaid base, means for removably holdingsaid core axi-' ally within said base, a priming tube pro jecting axially'through sald core, a ring secured on the lower end thereof above said first mentioned electrode, a second electrode integrally formed on the bottom and to one side of said ring, said second electrode disposed parallel and to one side of said first mentioned electrode and properl spaced therefrom to form a spark gap, an priming means secured on the upper end of said said tube and ring priming tube for holding in position.

5. In a spark plug, lower end tapered and recessed to form a rim, an apertured stamping seated insaid jecting axially through said core, a member removably secured on the lower projecting end of said means, and an upper electrode a base having thetip integrally formed on the bottom and to one side thereof and properly spaced to one side of said lower electrode tip to insure a proper spark gap between said upper and lower electrodes when the spark plug is assemble'd.

6. In a spark plug, a chambered base, a. chambered insulating core securely seated therein to form a combustion chamber within the spark plug, and electrodes secured to said base and core overlapping one another in the chamber of said insulating core and spaced apart to afiord a spark gap'therebetween.

In testimony whereof I have hereunto subscribing witnesses. FRANK ROBINSON.

Witnesses:

CHAS. O. ANDERSON, Tnoms Qu nn. 

